Simplified modelling and control of a synchronous machine with variable-speed six-step drive

We report on simple and intuitive techniques for the modelling of synchronous machines and their associated control systems. A scheme for control of electrical power flow is proposed for machines with variable-speed six-step drive. The scheme is developed with an eye toward efficient system operation, simple implementation, low latency in the control path and minimized cost of power electronics. Experimental results are presented for application of the control scheme to a homopolar inductor motor, as used in a flywheel energy storage system.